1. Field of the Invention
This invention relates to a method of detecting the presence of an emulsion in a brine. In particular, a method of detecting the presence of an emulsion in a turbid brine. This invention further relates to a method of differentiating between suspended particulate matter and the presence of an emulsion being the cause of turbidity in a completion brine.
2. Background Art
During the drilling of a wellbore, various fluids are typically used in the well for a variety of functions. The fluids may be circulated through a drill pipe and drill bit into the wellbore, and then may subsequently flow upward through wellbore to the surface. During this circulation, the drilling fluid may act to remove drill cuttings from the bottom of the hole to the surface, to suspend cuttings and weighting material when circulation is interrupted, to control subsurface pressures, to maintain the integrity of the wellbore until the well section is cased and cemented, to isolate the fluids from the formation by providing sufficient hydrostatic pressure to prevent the ingress of formation fluids into the wellbore, to cool and lubricate the drill string and bit, and/or to maximize penetration rate.
Drilling of an oil will proceeds in numerous steps. Once drilling operations of an oil well have been completed, the well is prepared for the completion operations, whereby the mud used for drilling is often displaced by a completion fluid. There are numerous methods of completing a well, amongst which are open hole completions, pre-drilled, liner, gravel packed screened systems, and the like. Clear, solids-free brines are used as completion/workover fluids for the purpose of controlling downhole formation pressures while reducing the risk of permanent formation damage resulting from solids invasion. These clear brine completion fluids are formulated and maintained to specifications which include density and clarity.
Determinations of well completion may be made via analysis of the completion fluid. Typically, a limit on the turbidity of the completion fluid is set, such that when the turbidity of the completion fluid falls below a certain level, the materials which were being removed by the completion fluid are considered to have been removed. Accordingly, once the turbidity of the completion fluid falls below a prescribed level, this part of the drilling process is complete.
Use of lubricants, petroleum coming from the well itself, and/or other additives used during one or more steps of the well drilling process may result in emulsions being formed within the completion fluid. Emulsions in completion fluids may result in turbid solutions, which resemble completion fluids emanating from a well which is not yet complete. The formation of a stable emulsion in a completion fluid thus frustrates the ability of those completing the well to determine when all the particulate matter has been removed from the well and thus, determining when this phase of the process has run to completion.
Accordingly, a need exists for a method of determining and/or differentiating between an emulsion and particulate matter in a brine, preferably in a completion fluid.